Selection system for a dual-element typewriter

ABSTRACT

A dual-element typewriter mounts the print elements a fixed distance apart with a carrier support system and operates each element from a single keyboard and selection system. A control is positionable to select the desired element. Each element is connected to opposite ends of a flexible strand and pulley system for rotating and tilting the elements to position the selected character at the print point. The control operates to prevent the rotation and tilting of one element so that the strand and pulley system moves only the element carrying the selected character to bring that character to the print point.

waited States Patent [72] Inventors DouglasE.Clancy; 8/1967 l-lickerson Jerome B. ODaniel, both of Lexington, Ky. 3,356,198 12/ l 967 Michelotti 888,689 2,919,002 12/1959 Palmer.........................

[21] Appl. No. [22] Flled 1969 Primary Examiner-Robert E. Pulfrey [45] Patented Nov. 16, 1971 73 A l te a] B M hi Assistant Examiner-Stephen C. Pellegrmo 1 Sslgnee n ma on usmess ac Attorneysl-lanifin & J ancin and David M. Bunnell Corporation 7 v Armonk, N.Y.

[54] SELECTION SYSTEM FOR A DUAL-ELEMENT TYPEWRITER 4 Claims, 5 Drawing Figs.

-element typewriter mounts the print elements a fixed distance apart with a carrier support system and operates each element from a single keyboard and selection system. A control is positionable to select the desired element. Each element is connected to opposite ends of a flexible strand and pulley system for rotating and tilting the elements to position the selected character at the print point. The conm u d A T C A R T s B A 1 8 4 8 luom w /2/l. 7 3. 2 ain-5 2 4 OMBMW 5 I821 .2 n/u n ":J" n u 4" m m m m m m m m S .l n :1 In 0 W C d S L d .l U h F 1 1 1 2 1 0 5 5 5 ..l .I. l.

trol operates to prevent the rotation and tilting of one element References Cited UNITED STATES PATENTS 9/1966 7 Segawa et a1.

PAIENTEDunv 1s IQTI sum 1 or a INVENTORS DOUGLAS E. CLANCY JEROME B. O'DANIEL BY MM ATTORNEY.

PAIENTEMuv 1s |97l SHEET 2 BF 3 FIG. 5

PAIENTEDuuv 16 I971 SHEET 3 BF 3 FIG. 4

FIG. 3

SELECTION SYSTEM FOR A DUAL-ELEMENT TYPEWRITER BACKGROUND OF THE INVENTION This invention relates generally to typewriters and, more particularly, to a dual-element printing head typewriter.

Single-element typewriters having readily interchangeable print elements such as, for example, those described in Palmer, U.S. Pat. No. 2,919,002, have achieved great commercial success. Although the character capacity can be increased by changing elements, in certain applications it is desirable to permit the operator to type more than the basic 88 characters without having to change type elements.

This invention provides for the doubling of the character capacity of the typewriter, utilizing a single selection system. The selection system is connected at all times to a pair of type elements but is structured to operate only one selected element at a time so that no additional load is placed on the system by the presence of the second element.

BRIEF SUMMARY OF THE INVENTION In accordance with this invention there is provided an apparatus for selectively causing either one of a pair of type elements to respond to a common selection system and printing mechanism of a typewriter. The apparatus comprises means moveable to connect one element and disconnect the other element from the printing mechanism and means moveable to permit the rotation and tilting of one element by the selection system and at the same time prevent the rotation and tilting of the other element by the selection system.

DESCRIPTION OF THE DRAWINGS The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention as illustrated in the accompanying drawings.

FIG. 1 is an exploded perspective view with parts broken away of an embodiment of the apparatus of the invention.

FIG. 2 is a top view with parts broken away of the embodiment illustrated in FIG. 1.

FIG. 3 is a top view with parts broken away of the embodiment illustrated in FIG. 1.

FIG. 4 is a side elevational view partially in section of the embodiment illustrated in FIG. 1.

FIG. 5 is a perspective view of the control and interlock system for the embodiment illustrated in FIGS. 1 and 2.

DETAILED DESCRIPTION Turning now to FIG. 1 a pair of print elements 11 and 13 each carrying an array of characters thereon are positioned side by side on a moveable carriage 15. The mounting of the elements 11 and 13 is identical. Each element is mounted for rotation and tilting about its center point and is moveable in a direction toward the printing point on a platen which is not shown. A detailed description of a suitable mounting is contained, for example, in U.S. Pat. No. 2,919,202. The movement of the elements to the print point is accomplished by the cyclic rotation of print cam 17 on print shaft 18 through print cam follower 19 which has two fingers 21 and 23. Follower 19 is slidably mounted on shaft 25 so that it can be translated to the right or left along an axis parallel to pring shaft 18 such that when finger 23 engages right rocker impression control assembly 27, finger 21 is moved out of contact with left rocker impression control assembly 29. This results in only the right rocker assembly being driven to the print point. Moving the follower to the left causes finger 21 to be engaged with left rocker impression control assembly 29 and disengages finger 23 from the right rocker impression control assembly 27 so that the left rocker is driven to the print point. The cam follower roller 31 slidably engages shaft 33 of follower 19 so that the position of roller 31 on cam 17 is not affected by the translation of follower 19. This makes the velocity control, provided by the moving of roller 31 to the left or right on the surface of cam 17, independent of which head is driven to the print point. The translation of follower 19 is accomplished through stud 35 which engages bifurcated portion 37 of shift bar 39.

The rotation of elements 11 and 13 is accomplished by a flexible strand and pulley system 41. Strand 43 is connected at one end to right rotate pulley 45 and at the other end to left rotate pulley 47. The rotate pulleys are biased by clock springs 50. Strand 43 passes from pulley 45 around reversing pulley 49, against guide pulley 51 through aperture 53in carriage 15, around shift arm pulley 55 to rotate arm pulley 57 and then to left rotate pulley 47. The rotate or shift motions are coupled to the right print element 13 in the condition shown by inhibiting the mou'on of left rotate pulley 47. This is accomplished by pin 59 fixed to bellcrank 61 which engages slot 63 in detent plate 65 which is rigidly coupled to rotate pulley 47. This has the effect of fixing or grounding the left end of strand 43. The right element 13 is rotated by changing the effective length of strand 43 the required amount to select the desired character. This occurs by moving pulleys 55 and 57 to the left or right by a selection system such as that described, for example, in U.S. Pat. No. 2,919,002.

When a character on left element 11 is to be selected bellcrank 61 is rotated about pivot shaft 62 in a clockwise direction to move pin 59 out of slot 63 in detent plate 65 by the action of shift bar 39 on pin 67 on end of bellcrank 61. At the same time pin 63 on bellcrank is moved into slot 68 of right-hand detent plate 69 which fixes or grounds the right end of strand 43 by preventing the rotation of pulley 45.

The tilting of elements 11 and 13 is accomplished by a flexible strand and pulley system 71. Strand 73 is connected at its right end to right tilt pulley 75 and at the other end to left tilt pulley 77. Strand 73 passes from pulley 75 around reversing pulley 48, against guide pulley 52, through aperture 53 in carriage 15, around pulley 77, to tilt arm pulley 79 and then to left tilt pulley 77. The tilt motion is coupled to the right print element 13 by the grounding of left rotate pulley 77. This is accomplished as shown by a slidably mounted detent plate 81 which engages detent pin 83 on tilt pulley 77 and prevents the rotation of pulley 77 thereby fixing or grounding the left end of strand 73. The right element 13 is then tilted by changing the effective length of strand 73 the required amount to select the desired character row. This is accomplished by moving pulley 79 to the left by a selection system such as the described, for example, in U.S. Pat. No. 2,919,002.

When a character on left element 11 is to be selected, detent plate 81 is moved out of engagement with pin 83 by the rotation of bellcrank 85 through the action of pin 67 (FIG. 2). At the same time slot 86 in detent plate 87 is moved into engagement with detent pin 89 on right tilt pulley 75 by the action of pin 91 attached to bellcrank 93 which rotates with bellcrank 65 on pivot shaft 95. This fixes the right end of strand 73 by preventing the rotation of pulley 75 so that the movement of tilt arm pulley 79 and strand 73 rotates left tilt pulley 77 to select the desired horizontal character row.

In operation, as further illustrated in FIGS. 2, 3 and 4 the selection of the desired element by moving the cam follower 19 into engagement with the selected rocker assembly and by grounding one set of tilt and rotate pulleys is accomplished in unison by moving shift bar 39, which is slidably mounted to the carrier 15 by pins 38 and 40 which engage slots 98 and 100, to the left or right. In the position shown the shift bar 39 is in the right-hand position. Bellcranks 61 and 65 are mounted in the opposite sense so that when shift bar 39 is moved to the left it moves pins 59 and 67 in a clockwise direction and frees pulley 47 for rotation. At the same time, pins 63 and 64 and bellcrank 65 move in a counterclockwise direction to lock pulley 45. Because bellcrank 85 is mounted on pivot shaft 62 it rotates with bellcrank 61 in a clockwise direction and moves detent plate 81 to the right and frees detent pin 83 and pulley 77 (FIG. 1) for rotation. The rotation of pivot shaft 95 in a counterclockwise direction moves bellcrank 93 and detent plate 87 to the left into engagement with detent pin 89 on tilt pulley 75 (FIG. 4). At the same time, the movement of shift bar 39 to the left slides follower 19 to the left so that finger 21 engages the left rocker assembly.

Shift bar 39 which is slidable mounted to the carrier 15 by pins 38 and 40 passing through slots 98 and 100 and is operated by bodine cable 101 attached to hood 103. Bar 39 is restored to the right by spring 105 attached to hook 107 at one end and to the carrier, (not shown) at the other.

Shift bar 39 is moveable by the mechanism illustrated in FIG. which is attached to the opposite end 108 of bodine cable 101. The shifting is accomplished by moving handle 109 of bistable code bar 111 to the left or right to cause cam follower 113 to move cable 101. Code bar 111 assures that the shifting between the two elements takes place in the lower case mode and when the selection system is in the home position. The structure and operation of the cycle clutch 110 is shown, for example, in U.S. Pat. No. 3,086,635. If the cycle clutch 110 is not in the home position but has been unlatched, clutch 110 is moved to the left by spring 120. End 114 of member 115 then engages the left-hand slot 116a of a pair of slots 1 16a and 1l6b so that code bar is locked in position until the cycle clutch returns to the home position. If member 115 is misaligned with both slots 116a and b then its operation is inhibited until code bar 11] reaches a bistable position. Shift bar 117 movement can only take place when arm 119 is lined up with some of slots 118a and 118b. When the shift bar is depressed, arm 119 locks code bar 111 in one or the other of slots 118a and 11811 until the shift is released.

The movement of the selected type element to the desired print point on the copy sheet can be accomplished in a variety of ways, for example, either by moving the carriage, the rocker assemblies, by providing a moveable platen, or a combination of the above.

The relative rotation of the heads can be changed, for example, by eliminating the reversing pulley and adjusting the character location on the type element or by complementing the rotate selection logic when using the right-hand element.

it can be seen from the above description that the apparatus of the invention provides character selection for either of two type elements from a single tape selection system. This is accomplished by selectively grounding either end of the tilt and rotate tapes to produce two outputs. A major advantage of this apparatus is that the selection system and tapes are not subjected to increased dynamic loads due to the addition of the second type element.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.

We claim:

1. In a typewriter including a keyboard, keylevers, a selection system, a printing mechanism, and a pair of type elements operatively connected thereto, each element being mounted for rotation and tilting about a center point and having a plurality of characters arranged thereon, an apparatus for selectively causing either one of the other of said elements to respond to said selection system and said printing mechanism said apparatus comprising:

1. a first flexible strand having its opposite ends connected to support means for rotating each head,

2. means connected to said selection system for varying the length of said first strand according to the keylever selected,

3. a second flexible strand having its opposite ends connected to support means for tilting each head,

4. means connected to said selection system for varying the length of said second strand according to the keylever selected, and

5. control means positionable to select either one or the other of said elements for response, said control means including:

a. locking means moveable to prevent the rotation and tilting of the element not selected for response and thereby fix the ends of said strands connected to the means for rotating and the means for tilting the element not selected for response and at the same time moveable to permit the rotation and tilting of the element selected for response caused by the movement of the ends of said strands connected to the means for rotating and the means for tilting the element selected according to the change in lengths of said strands, and

b. means moveable to connect the element selected for response to said printing mechanism and at the same time moveable to disconnect the element not selected for response from said printing mechanism.

2. The apparatus of claim 1 wherein said locking means comprises a pair of pins alternately moveable into engagement with a pair of detent plates fixed to said support means for rotating each head and a pair of detent plates alternately moveable into engagement with a pair of pins fixed to said support means for tilting each head.

3. The apparatus of claim 1 wherein said control means includes a bistable code bar which engages the cycle clutch and prevents movement of said control when said clutch is not in the home position and which prevents operation of said cycle clutch when said code bar is not in a bistable position.

4. The apparatus of claim 3 wherein said bistable code bar engages the shift bar and prevents movement of said shift bar when said code bar is not in a bistable position. 

1. In a typewriter including a keyboard, keylevers, a selection system, a printing mechanism, and a pair of type elements operatively connected thereto, each element being mounted for rotation and tilting about a center point and having a plurality of characters arranged thereon, an apparatus for selectively causing either one of the other of said elements to respond to said selection system and said printing mechanism said apparatus comprising:
 1. a first flexible strand having its opposite ends connected to support means for rotating each head,
 2. means connected to said selection system for varying the length of said first strand according to the keylever selected,
 3. a second flexible strand having its opposite ends connected to support means for tilting each head,
 4. means connected to said selection system for varying the length of said second strand according to the keylever selected, and
 5. control means positionable to select either one or the other of said elements for response, said control means including: a. locking means moveable to prevent the rotation and tilting of the element not selected for response and thereby fix the ends of said strands connected to the means for rotating and the means for tilting the element not selected for response and at the same time moveable to permit the rotation and tilting of the element selected for response caused by the movement of the ends of said strands connected to the means for rotating and the means for tilting the element selected according to the change in lengths of said strands, and b. means moveable to connect the element selected for response to said printing mechanism and at the same time moveable to disconnect the element not selected for response from said printing mechanism.
 2. The apparatus of claim 1 wherein said locking means comprises a pair of pins alternately moveable into engagement with a pair of detent plates fixed to said support means for rotating each head and a pair of detent plates alternately moveable into engagement with a pair of pins fixed to said support means for tilting each head.
 2. means connected to said selection system for varying the length of said first strand according to the keylever selected,
 3. a second flexible strand having its opposite ends connected to support means for tilting each head,
 3. The apparatus of claim 1 wherein said control means includes a bistable code bar which engages the cycle clutch and prevents movement of said control when said clutch is not in the home position and which prevents operation of said cycle clutch when said code bar is not in a bistable position.
 4. The apparatus of claim 3 wherein said bistable code bar engages the shift bar and prevents movement of said shift bar when said code bar is not in a bistable position.
 4. means connected to said selection system for varying the length of said second strand according to the keylever selected, and
 5. control means positionable to select either one or the other of said elements for response, said control means including: a. locking means moveable to prevent the rotation and tilting of the element not selected for response and thereby fix the ends of said strands connected to the means for rotating and the means for tilting the element not selected for response and at the same time moveable to permit the rotation and tilting of the element selected for response caused by the movement of the ends of said strands connected to the means for rotating and the means for tilting the element selected according to the change in lengths of said strands, and b. means moveable to connect the element selected for response to said printing mechanism and at the same time moveable to disconnect the element not selected for response from said printing mechanism. 